Modified pusher apparatus

ABSTRACT

Placement of a stent having a tethered ferromagnetic bead may be facilitated with a modified pusher having an opening at the distal end of the pusher to receive the tethered ferromagnetic bead. The ferromagnetic bead may be positioned within the bladder whereby a tether connection to a shortened stent ending within the ureter may be used to reduce the likelihood of patient irritation. The bead, tether, and stent assembly may be advanced into the patient as a unit along a conventional guide wire and using a conventional cystoscope.

RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.14/401,933, filed Nov. 18, 2014, which is the U.S. national stageapplication of International application number PCT/CA2013/000438, filedMay 3, 2013, which claims the benefit of U.S. Provisional ApplicationSer. No. 61/649,102, filed May 18, 2012; the disclosures of which arehereby incorporated by reference in their entireties.

TECHNICAL FIELD

This invention relates to the field of stent placement, where the stentmay be used to keep open body channels. In particular, the inventionrelates to a stent placement pusher apparatus.

BACKGROUND

Stents are used to keep open body channels. For example, ureteral stentsmay provide drainage of urine from the kidneys to the bladder.Similarly, biliary stents may provide drainage of the bile ducts betweenthe liver and gallbladder and between the gallbladder and smallintestine. A stent is a flexible, tubular structure that is made fromrelatively inert materials (for example, silicon, teflon™, polyethylene,polyurethane, stainless steel, or nickel-titanium alloy). Often a stentmay be perforated to provide small drainage holes along its length.Stents may also be shaped to define “hooks” at either end. For example,such hooks may prevent migration of a ureteral stent from the kidneytoward the bladder or from the bladder upwards. A shortened ureteralstent has only one hook at the distal or kidney end of the stent. Often,shortened stents are used to reduce irritation caused by the presence ofa stent within the lower ureter and within the bladder. With a shortenedstent, the stent resides in the ureter, remote from the bladder and theureteral orifice (i.e. the junction of the ureter and the bladder).

Indwelling stents periodically need to be removed or periodicallyreplaced. Conventional stent removal procedures may be complex and maybe painful, sometimes requiring general anesthesia.

A thin thread may be attached to a shortened stent to extend into thebladder to assist with the removal of the stent. However, such ashortened stent (with thread) requires endoscopic visualization of thethreads so that they may be grasped, and the stent may be withdrawn.Although this is a relatively simple procedure, it requires specializedinstruments used by an urologist in a sterile setting. Nevertheless,general anesthesia may also be required.

An alternative stent removal method is described in WO 99/58083, whichemploys the use of a tethered bead at the proximal or bladder end of thestent that may be removed with the aid of magnet tipped catheter.

SUMMARY

The pusher apparatus or pusher attachment apparatus attached to a pusherdescribed herein allow for the insertion of a shortened stent (the stenthaving a bead suspended by a tether) into a patient's ureter 90 withoutthe need for a positioning line to withdraw the bead from the ureter 90during positioning of the stent. Using the modified pusher apparatusdescribed herein or pusher attachment apparatus attached to a pusher,the bead does not need to be pushed past the ureteral orifice 85 andinto the ureter 90, but remains within the pusher receptacle 17 and canstay within the bladder. Accordingly, the pusher apparatus describedherein may reduce irritation to the patient's ureter and simplify theinsertion, when used with a shortened stent with a tethered bead.

In accordance with one embodiment, there is provided an apparatus forthe insertion of a shortened stent, said stent having a bead suspendedby a tether, wherein, the pusher includes: (a) a hollow tube having adistal end and a proximal end; and (b) an opening defined in theperipheral wall of the pusher near the distal end, which reaches theinner hollow portion of the pusher and may be sized to allow for thepositioning of the bead into the opening and at least partially withinthe receptacle defined by the opening.

In accordance with another embodiment, there is provided a pusherapparatus, for the insertion of a shortened stent, said stent having abead suspended by a tether, wherein, the pusher includes: (a) a hollowtube having a distal end and a proximal end; and (b) an opening definedin the peripheral wall of the pusher near the distal end, which extendsinto the inner hollow portion of the pusher and may be sized to allowfor the positioning of the bead into the opening and at least partiallywithin the receptacle defined by the opening.

In accordance with another embodiment, there is provided a pusherapparatus, for the insertion of a shortened stent, said stent having abead suspended by a tether, wherein, the pusher includes: (a) a hollowtube having a distal end and a proximal end; and (b) an opening definedin the peripheral wall of the pusher near the distal end, which reachesthe inner hollow portion of the pusher and may be sized to allow for thepositioning of the bead through the opening and within the receptacledefined by the opening.

In accordance with another embodiment, there is provided a pusherapparatus, for the insertion of a shortened stent, said stent having abead suspended by a tether, wherein, the pusher includes: (a) a hollowtube having a distal end and a proximal end; and (b) an opening definedin the peripheral wall of the pusher near the distal end, which reachesthe inner hollow portion of the pusher and may be sized to allow for thepositioning of the bead through the opening and within the pusher.

In accordance with another embodiment, there is provided a pusherapparatus, including: (a) a hollow tube with a distal end and a proximalend; and (b) an opening defined in the peripheral wall of the pushernear the distal end, which reaches the inner hollow portion of thepusher and may be sized to allow for positioning of a tethered bead intothe opening and at least partially within the pusher.

In accordance with another embodiment, there is provided a pusherattachment apparatus, including: (a) a hollow tube having a distal endand a proximal end; (b) a connector at the proximal end of the hollowtube for attachment to a pusher having a lumen, whereby the lumen of thepusher may be contiguous with the lumen of the hollow tube; and (c) anopening defined in the peripheral wall of the hollow tube, which extendsto the inner hollow portion of the hollow tube and may be sized to allowfor positioning of a tethered bead into the opening and at leastpartially within the receptacle defined by the opening.

In accordance with another embodiment, there is provided a pusherattachment apparatus, including: (a) a hollow tube having a distal endand a proximal end; (b) a connector at the proximal end of the hollowtube for attachment to a pusher having a lumen, whereby the lumen of thepusher may be contiguous with the lumen of the hollow tube; and (c) anopening defined in the peripheral wall of the hollow tube, which reachesthe inner hollow portion of the hollow tube and may be sized to allowfor positioning of a tethered bead into the opening and at leastpartially within the pusher attachment apparatus.

In accordance with another embodiment, there is provided a commercialpackage including: (a) a guide wire over which a stent may be pushed;(b) a stent assembly for keeping open body channels and having atethered bead for stent retrieval, the stent and bead being adapted tobe pushed over the guide wire; (c) a pusher attachment, as describedherein, adapted to be pushed over the guide wire to advance the stentrelative to the guide wire and to accept the tethered bead within theopening; and (d) a pusher tube adapted to be pushed over the guide wirefor advancing the stent relative to the guide wire.

In accordance with another embodiment, there is provided a commercialpackage comprising: (a) a guide wire over which a stent may be pushed;(b) a stent assembly for keeping open body channels and having atethered bead for stent retrieval, the stent and bead being adapted tobe pushed over the guide wire; and (c) a pusher apparatus, as describedherein, adapted to be pushed over the guide wire to advance the stentrelative to the guide wire and to accept the tethered bead into theopening.

The guide wire, the stent assembly, the pusher attachment, and thepusher tube may be for use in delivering the stent assembly to a humanureter. The guide wire, the stent assembly, and the pusher apparatus maybe for use in delivering the stent assembly to a human ureter.

The outer diameter of the hollow tube may be less than the diameter ofthe bead, provided that the pusher apparatus with a bead positionedwithin the receptacle is able to pass through the lumen of a cytoscope.The outer diameter of the hollow tube may be approximately the diameterof the bead. The outer diameter of the hollow tube may be greater thanthe diameter of the bead.

Alternatively, the outer diameter of the hollow tube may be greater thanthe diameter of the bead plus the cross-sectional area of the peripheralwall of the pusher opposite the opening. The outer diameter of thehollow tube may be less than the diameter of the bead plus thecross-sectional area of the peripheral wall of the pusher opposite theopening, provided that the pusher apparatus with a bead positionedwithin the receptacle is able to pass through the lumen of a cytoscope.The outer diameter of the hollow tube may be approximately the diameterof the bead plus the cross-sectional area of the peripheral wall of thepusher opposite the opening.

The opening may be greater than 180° of the circumference of the pusher.The opening may be greater than 185° of the circumference of the pusher.The opening may be greater than 190° of the circumference of the pusher.The opening may be greater than 195° of the circumference of the pusher.The opening may be greater than 200° of the circumference of the pusher.The opening may be greater than 205° of the circumference of the pusher.The opening may be greater than 210° of the circumference of the pusher.The opening may be greater than 210° of the circumference of the pusher.The opening may be greater than 215° of the circumference of the pusher.The opening may be greater than 220° of the circumference of the pusher.The opening may be greater than 225° of the circumference of the pusher.The opening may be greater than 230° of the circumference of the pusher.The opening may be greater than 235° of the circumference of the pusher.The opening may be greater than 240° of the circumference of the pusher.The opening may be greater than 250° of the circumference of the pusher.The opening may be greater than 255° of the circumference of the pusher.The opening may be greater than 260° of the circumference of the pusher.The opening may be greater than 265° of the circumference of the pusher.The opening may be greater than 270° of the circumference of the pusher.The opening may be greater than 280° of the circumference of the pusher.The opening may be greater than 285° of the circumference of the pusher.The opening may be greater than 290° of the circumference of the pusher.The opening may be greater than 295° of the circumference of the pusher.The opening may be greater than 300° of the circumference of the pusher.The opening may be greater than 305° of the circumference of the pusher.The opening may be greater than 310° of the circumference of the pusher.The opening may be greater than 315° of the circumference of the pusher.The opening may be greater than 320° of the circumference of the pusher.The opening may be greater than 325° of the circumference of the pusher.The opening may be greater than 330° of the circumference of the pusher.The opening may be greater than 335° of the circumference of the pusher.The opening may be greater than 340° of the circumference of the pusher.The opening may be greater than 345° of the circumference of the pusher.The opening may be greater than 350° of the circumference of the pusher.The opening may be greater than 355° of the circumference of the pusher.

The area adjacent the opening may be reinforced to maintain structuralintegrity of the pusher tube. The reinforcement may be by the additionof a material that is less flexible than the pusher. The reinforcementmay be by the use of a material that is less flexible than the pushertube adjacent the opening.

The minimum distance between the distal end of the pusher and theopening may be about 3 cm. The minimum distance between the distal endof the pusher and the opening may be about 2.5 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 5.0cm. The minimum distance between the distal end of the pusher and theopening may be about 4.9 cm. The minimum distance between the distal endof the pusher and the opening may be about 4.8 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 4.7cm. The minimum distance between the distal end of the pusher and theopening may be about 4.6 cm. The minimum distance between the distal endof the pusher and the opening may be about 4.5 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 4.4cm. The minimum distance between the distal end of the pusher and theopening may be about 4.3 cm. The minimum distance between the distal endof the pusher and the opening may be about 4.2 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 4.1cm. The minimum distance between the distal end of the pusher and theopening may be about 4.0 cm. The minimum distance between the distal endof the pusher and the opening may be about 3.9 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 3.8cm. The minimum distance between the distal end of the pusher and theopening may be about 3.7 cm. The minimum distance between the distal endof the pusher and the opening may be about 3.6 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 3.5cm. The minimum distance between the distal end of the pusher and theopening may be about 3.4 cm. The minimum distance between the distal endof the pusher and the opening may be about 3.3 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 3.2cm. The minimum distance between the distal end of the pusher and theopening may be about 3.1 cm. The minimum distance between the distal endof the pusher and the opening may be about 2.9 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 2.8cm. The minimum distance between the distal end of the pusher and theopening may be about 2.7 cm. The minimum distance between the distal endof the pusher and the opening may be about 2.6 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 2.4cm. The minimum distance between the distal end of the pusher and theopening may be about 2.3 cm. The minimum distance between the distal endof the pusher and the opening may be about 2.2 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 2.1cm. The minimum distance between the distal end of the pusher and theopening may be about 2.0 cm. The minimum distance between the distal endof the pusher and the opening may be about 1.9 cm. The minimum distancebetween the distal end of the pusher and the opening may be betweenabout 4 cm and 10 cm. The minimum distance between the distal end of thepusher and the opening may be between about 5 cm and 8 cm. The minimumdistance between the distal end of the pusher and the opening may bebetween about 5 cm and 10 cm. The minimum distance between the distalend of the pusher and the opening may be between about 5 cm and 9 cm.The minimum distance between the distal end of the pusher and theopening may be between about 5 cm and 7 cm. The minimum distance betweenthe distal end of the pusher and the opening may be between about 5 cmand 6 cm. The minimum distance between the distal end of the pusher andthe opening may be between about 4 cm and 10 cm. The minimum distancebetween the distal end of the pusher and the opening may be betweenabout 4 cm and 9 cm. The minimum distance between the distal end of thepusher and the opening may be between about 4 cm and 8 cm. The minimumdistance between the distal end of the pusher and the opening may bebetween about 4 cm and 7 cm. The minimum distance between the distal endof the pusher and the opening may be between about 4 cm and 6 cm. Theminimum distance between the distal end of the pusher and the openingmay be between about 3 cm and 12 cm. The minimum distance between thedistal end of the pusher and the opening may be between about 3 cm and11 cm. The minimum distance between the distal end of the pusher and theopening may be between about 3 cm and 10 cm. The minimum distancebetween the distal end of the pusher and the opening may be betweenabout 3 cm and 9 cm. The minimum distance between the distal end of thepusher and the opening may be between about 3 cm and 8 cm. The minimumdistance between the distal end of the pusher and the opening may bebetween about 2 cm and 10 cm.

The minimum distance between the distal end of the pusher attachment andthe opening may be about 3 cm. The minimum distance between the distalend of the pusher attachment and the opening may be about 2.5 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 5.0 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 4.9 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 4.8 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 4.7 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 4.6 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 4.5 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 4.4 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 4.3 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 4.2 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 4.1 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 4.0 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 3.9 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 3.8 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 3.7 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 3.6 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 3.5 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 3.4 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 3.3 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 3.2 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 3.1 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 2.9 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 2.8 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 2.7 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 2.6 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 2.4 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 2.3 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 2.2 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 2.1 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 2.0 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 1.9 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be between about 4 cm and 10 cm. The minimum distancebetween the distal end of the pusher attachment and the opening may bebetween about 5 cm and 8 cm. The minimum distance between the distal endof the pusher attachment and the opening may be between about 5 cm and10 cm. The minimum distance between the distal end of the pusherattachment and the opening may be between about 5 cm and 9 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be between about 5 cm and 7 cm. The minimum distance betweenthe distal end of the pusher attachment and the opening may be betweenabout 5 cm and 6 cm. The minimum distance between the distal end of thepusher attachment and the opening may be between about 4 cm and 10 cm.The minimum distance between the distal end of the pusher attachment andthe opening may be between about 4 cm and 9 cm. The minimum distancebetween the distal end of the pusher attachment and the opening may bebetween about 4 cm and 8 cm. The minimum distance between the distal endof the pusher attachment and the opening may be between about 4 cm and 7cm. The minimum distance between the distal end of the pusher attachmentand the opening may be between about 4 cm and 6 cm. The minimum distancebetween the distal end of the pusher attachment and the opening may bebetween about 3 cm and 12 cm. The minimum distance between the distalend of the pusher attachment and the opening may be between about 3 cmand 11 cm. The minimum distance between the distal end of the pusherattachment and the opening may be between about 3 cm and 10 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be between about 3 cm and 9 cm. The minimum distance betweenthe distal end of the pusher attachment and the opening may be betweenabout 3 cm and 8 cm.

The pusher apparatus described herein allows for the insertion of ashortened stent (the stent having a bead suspended by a tether) into apatient's ureter 90 without the need for a positioning line to withdrawthe bead from the ureter 90 during positioning of the stent. Using themodified pusher apparatus described herein, the bead does not need to bepushed past the uretal orifice 85 and into the ureter 90, but remainswithin the pusher receptacle 17 and can stay within the bladder.Accordingly, the pusher apparatus described herein may reduce irritationto the patient's ureter and simplify the insertion, when a shortenedstent with a tethered bead is used.

In accordance with one embodiment, there is provided an apparatus forthe insertion of a shortened stent, said stent having a bead suspendedby a tether, wherein, the pusher includes: (a) a hollow tube having adistal end and a proximal end; and (b) an opening defined in theperipheral wall of the pusher near the distal end, which reaches theinner hollow portion of the pusher and may be sized to allow for thepositioning of the bead through the opening and within the receptacledefined by the opening.

In accordance with another embodiment, there is provided a pusherapparatus, for the insertion of a shortened stent, said stent having abead suspended by a tether, wherein, the pusher includes: (a) a hollowtube having a distal end and a proximal end; and (b) an opening definedin the peripheral wall of the pusher near the distal end, which reachesthe inner hollow portion of the pusher and may be sized to allow for thepositioning of the bead through the opening and within the receptacledefined by the opening.

In accordance with another embodiment, there is provided a pusherapparatus, for the insertion of a shortened stent, said stent having abead suspended by a tether, wherein, the pusher includes: (a) a hollowtube having a distal end and a proximal end; and (b) an opening definedin the peripheral wall of the pusher near the distal end, which reachesthe inner hollow portion of the pusher and may be sized to allow for thepositioning of the bead through the opening and within the pusher.

In accordance with another embodiment, there is provided a pusherapparatus, including: (a) a hollow tube with a distal end and a proximalend; and (b) an opening defined in the peripheral wall of the pushernear the distal end, which reaches the inner hollow portion of thepusher and may be sized to allow for positioning of a tethered beadthrough the opening and within the pusher.

In accordance with another embodiment, there is provided a pusherattachment apparatus, including: (a) a hollow tube having a distal endand a proximal end; (b) a connector at the proximal end of the hollowtube for attachment to a pusher having a lumen, whereby the lumen of thepusher may be contiguous with the lumen of the hollow tube; and (c) anopening defined in the peripheral wall of the hollow tube, which reachesthe inner hollow portion of the hollow tube and may be sized to allowfor positioning of a tethered bead through the opening and within thereceptacle defined by the opening.

In accordance with another embodiment, there is provided a pusherattachment apparatus, including: (a) a hollow tube having a distal endand a proximal end; (b) a connector at the proximal end of the hollowtube for attachment to a pusher having a lumen, whereby the lumen of thepusher may be contiguous with the lumen of the hollow tube; and (c) anopening defined in the peripheral wall of the hollow tube, which reachesthe inner hollow portion of the hollow tube and may be sized to allowfor positioning of a tethered bead through the opening and within thepusher attachment apparatus.

In accordance with another embodiment, there is provided a commercialpackage including: (a) a guide wire over which a stent may be pushed;(b) a stent assembly for keeping a body channel open and having atethered bead for stent retrieval, the stent and bead being adapted tobe pushed over the guide wire; (c) a pusher attachment, as describedherein, adapted to be pushed over the guide wire to advance the stentrelative to the guide wire and to accept the tethered bead within theopening; and (d) a pusher tube adapted to be pushed over the guide wirefor advancing the stent relative to the guide wire.

In accordance with another embodiment, there is provided a commercialpackage including: (a) a guide wire over which a stent may be pushed;(b) a stent assembly for keeping a body channel open and having atethered bead for stent retrieval, the stent and bead being adapted tobe pushed over the guide wire; and (c) a pusher apparatus, as describedherein, adapted to be pushed over the guide wire to advance the stentrelative to the guide wire and to accept the tethered bead within theopening.

In accordance with another embodiment, there is provided a commercialpackage including (a) a stent assembly for keeping a body channel openand having a tethered bead for stent retrieval, the stent and bead beingadapted to be pushed over a guide wire; (b) a pusher attachment asdescribed herein adapted to be pushed over the guide wire to advance thestent relative to the guide wire and to accept the tethered bead withinthe opening, wherein the tethered bead is retained within the opening byan holder until a guide wire is inserted; and (c) a pusher tube adaptedto be pushed over the guide wire for advancing the stent relative to theguide wire.

In accordance with another embodiment, there is provided a commercialpackage including (a) a stent assembly for keeping a body channel openand having a tethered bead for stent retrieval, the stent and bead beingadapted to be pushed over a guide wire; and (b) a pusher apparatus asdescribed herein adapted to be pushed over the guide wire to advance thestent relative to the guide wire and to accept the tethered bead withinthe opening, wherein the tethered bead is retained within the opening byan holder until a guide wire is inserted.

In accordance with another embodiment, there is provided a commercialpackage including (a) a stent assembly for keeping a body channel openand having a tethered bead for stent retrieval, the stent and bead beingadapted to be pushed over a guide wire; (b) a pusher attachment asdescribed herein adapted to be pushed over the guide wire to advance thestent relative to the guide wire and to accept the tethered bead withinthe opening, wherein the tethered bead is retained within the opening byan external holder until a guide wire is inserted; and (c) a pusher tubeadapted to be pushed over the guide wire for advancing the stentrelative to the guide wire.

In accordance with another embodiment, there is provided a commercialpackage including (a) a stent assembly for keeping a body channel openand having a tethered bead for stent retrieval, the stent and bead beingadapted to be pushed over a guide wire; and (b) a pusher apparatus asdescribed herein adapted to be pushed over the guide wire to advance thestent relative to the guide wire and to accept the tethered bead withinthe opening, wherein the tethered bead is retained within the opening byan external holder until a guide wire is inserted.

In accordance with another embodiment, there is provided a commercialpackage including (a) a stent assembly for keeping a body channel openand having a tethered bead for stent retrieval, the stent and bead beingadapted to be pushed over a guide wire; (b) a pusher attachment asdescribed herein adapted to be pushed over the guide wire to advance thestent relative to the guide wire and to accept the tethered bead withinthe opening, wherein the tethered bead is retained within the opening byan internal holder until a guide wire is inserted; and (c) a pusher tubeadapted to be pushed over the guide wire for advancing the stentrelative to the guide wire.

In accordance with another embodiment, there is provided a commercialpackage including (a) a stent assembly for keeping a body channel openand having a tethered bead for stent retrieval, the stent and bead beingadapted to be pushed over a guide wire; and (b) a pusher apparatus asdescribed herein adapted to be pushed over the guide wire to advance thestent relative to the guide wire and to accept the tethered bead withinthe opening, wherein the tethered bead is retained within the opening byan internal holder until a guide wire is inserted.

The holder may internal or external or a combination of both. The holdermay be a wrapper. The holder may be a mandrel.

The outer diameter of the hollow tube may be less than the diameter ofthe bead, provided that the pusher apparatus with a bead positionedwithin the receptacle is able to pass through the lumen of a cytoscope.The outer diameter of the hollow tube may be approximately the diameterof the bead. The outer diameter of the hollow tube may be greater thanthe diameter of the bead.

Alternatively, the outer diameter of the hollow tube may be greater thanthe diameter of the bead plus the cross-sectional area of the peripheralwall of the pusher opposite the opening. The outer diameter of thehollow tube may be less than the diameter of the bead plus thecross-sectional area of the peripheral wall of the pusher opposite theopening, provided that the pusher apparatus with a bead positionedwithin the receptacle is able to pass through the lumen of a cytoscope.The outer diameter of the hollow tube may be approximately the diameterof the bead plus the cross-sectional area of the peripheral wall of thepusher opposite the opening.

The opening may be greater than 180° of the circumference of the pusher.The opening may be greater than 185° of the circumference of the pusher.The opening may be greater than 190° of the circumference of the pusher.The opening may be greater than 195° of the circumference of the pusher.The opening may be greater than 200° of the circumference of the pusher.The opening may be greater than 205° of the circumference of the pusher.The opening may be greater than 210° of the circumference of the pusher.The opening may be greater than 210° of the circumference of the pusher.The opening may be greater than 215° of the circumference of the pusher.The opening may be greater than 220° of the circumference of the pusher.The opening may be greater than 225° of the circumference of the pusher.The opening may be greater than 230° of the circumference of the pusher.The opening may be greater than 235° of the circumference of the pusher.The opening may be greater than 240° of the circumference of the pusher.The opening may be greater than 250° of the circumference of the pusher.The opening may be greater than 255° of the circumference of the pusher.The opening may be greater than 260° of the circumference of the pusher.The opening may be greater than 265° of the circumference of the pusher.The opening may be greater than 270° of the circumference of the pusher.The opening may be greater than 280° of the circumference of the pusher.The opening may be greater than 285° of the circumference of the pusher.The opening may be greater than 290° of the circumference of the pusher.The opening may be greater than 295° of the circumference of the pusher.The opening may be greater than 300° of the circumference of the pusher.The opening may be greater than 305° of the circumference of the pusher.The opening may be greater than 310° of the circumference of the pusher.The opening may be greater than 315° of the circumference of the pusher.The opening may be greater than 320° of the circumference of the pusher.The opening may be greater than 325° of the circumference of the pusher.The opening may be greater than 330° of the circumference of the pusher.The opening may be greater than 335° of the circumference of the pusher.The opening may be greater than 340° of the circumference of the pusher.The opening may be greater than 345° of the circumference of the pusher.The opening may be greater than 350° of the circumference of the pusher.The opening may be greater than 355° of the circumference of the pusher.

The area adjacent the opening may be reinforced to maintain structuralintegrity of the pusher tube. The reinforcement may be by the additionof a material that is less flexible than the pusher. The reinforcementmay be by the use of a material that is less flexible than the pushertube adjacent the opening.

The minimum distance between the distal end of the pusher and theopening may be about 3 cm. The minimum distance between the distal endof the pusher and the opening may be about 2.5 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 5.0cm. The minimum distance between the distal end of the pusher and theopening may be about 4.9 cm. The minimum distance between the distal endof the pusher and the opening may be about 4.8 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 4.7cm. The minimum distance between the distal end of the pusher and theopening may be about 4.6 cm. The minimum distance between the distal endof the pusher and the opening may be about 4.5 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 4.4cm. The minimum distance between the distal end of the pusher and theopening may be about 4.3 cm. The minimum distance between the distal endof the pusher and the opening may be about 4.2 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 4.1cm. The minimum distance between the distal end of the pusher and theopening may be about 4.0 cm. The minimum distance between the distal endof the pusher and the opening may be about 3.9 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 3.8cm. The minimum distance between the distal end of the pusher and theopening may be about 3.7 cm. The minimum distance between the distal endof the pusher and the opening may be about 3.6 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 3.5cm. The minimum distance between the distal end of the pusher and theopening may be about 3.4 cm. The minimum distance between the distal endof the pusher and the opening may be about 3.3 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 3.2cm. The minimum distance between the distal end of the pusher and theopening may be about 3.1 cm. The minimum distance between the distal endof the pusher and the opening may be about 2.9 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 2.8cm. The minimum distance between the distal end of the pusher and theopening may be about 2.7 cm. The minimum distance between the distal endof the pusher and the opening may be about 2.6 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 2.4cm. The minimum distance between the distal end of the pusher and theopening may be about 2.3 cm. The minimum distance between the distal endof the pusher and the opening may be about 2.2 cm. The minimum distancebetween the distal end of the pusher and the opening may be about 2.1cm. The minimum distance between the distal end of the pusher and theopening may be about 2.0 cm. The minimum distance between the distal endof the pusher and the opening may be about 1.9 cm. The minimum distancebetween the distal end of the pusher and the opening may be betweenabout 4 cm and 10 cm. The minimum distance between the distal end of thepusher and the opening may be between about 5 cm and 8 cm. The minimumdistance between the distal end of the pusher and the opening may bebetween about 5 cm and 10 cm. The minimum distance between the distalend of the pusher and the opening may be between about 5 cm and 9 cm.The minimum distance between the distal end of the pusher and theopening may be between about 5 cm and 7 cm. The minimum distance betweenthe distal end of the pusher and the opening may be between about 5 cmand 6 cm. The minimum distance between the distal end of the pusher andthe opening may be between about 4 cm and 10 cm. The minimum distancebetween the distal end of the pusher and the opening may be betweenabout 4 cm and 9 cm. The minimum distance between the distal end of thepusher and the opening may be between about 4 cm and 8 cm. The minimumdistance between the distal end of the pusher and the opening may bebetween about 4 cm and 7 cm. The minimum distance between the distal endof the pusher and the opening may be between about 4 cm and 6 cm. Theminimum distance between the distal end of the pusher and the openingmay be between about 3 cm and 12 cm. The minimum distance between thedistal end of the pusher and the opening may be between about 3 cm and11 cm. The minimum distance between the distal end of the pusher and theopening may be between about 3 cm and 10 cm. The minimum distancebetween the distal end of the pusher and the opening may be betweenabout 3 cm and 9 cm. The minimum distance between the distal end of thepusher and the opening may be between about 3 cm and 8 cm. The minimumdistance between the distal end of the pusher and the opening may bebetween about 2 cm and 10 cm.

The minimum distance between the distal end of the pusher attachment andthe opening may be about 3 cm. The minimum distance between the distalend of the pusher attachment and the opening may be about 2.5 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 5.0 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 4.9 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 4.8 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 4.7 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 4.6 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 4.5 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 4.4 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 4.3 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 4.2 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 4.1 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 4.0 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 3.9 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 3.8 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 3.7 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 3.6 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 3.5 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 3.4 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 3.3 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 3.2 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 3.1 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 2.9 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 2.8 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 2.7 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 2.6 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 2.4 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 2.3 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 2.2 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 2.1 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be about 2.0 cm. The minimum distance between the distal endof the pusher attachment and the opening may be about 1.9 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be between about 4 cm and 10 cm. The minimum distancebetween the distal end of the pusher attachment and the opening may bebetween about 5 cm and 8 cm. The minimum distance between the distal endof the pusher attachment and the opening may be between about 5 cm and10 cm. The minimum distance between the distal end of the pusherattachment and the opening may be between about 5 cm and 9 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be between about 5 cm and 7 cm. The minimum distance betweenthe distal end of the pusher attachment and the opening may be betweenabout 5 cm and 6 cm. The minimum distance between the distal end of thepusher attachment and the opening may be between about 4 cm and 10 cm.The minimum distance between the distal end of the pusher attachment andthe opening may be between about 4 cm and 9 cm. The minimum distancebetween the distal end of the pusher attachment and the opening may bebetween about 4 cm and 8 cm. The minimum distance between the distal endof the pusher attachment and the opening may be between about 4 cm and 7cm. The minimum distance between the distal end of the pusher attachmentand the opening may be between about 4 cm and 6 cm. The minimum distancebetween the distal end of the pusher attachment and the opening may bebetween about 3 cm and 12 cm. The minimum distance between the distalend of the pusher attachment and the opening may be between about 3 cmand 11 cm. The minimum distance between the distal end of the pusherattachment and the opening may be between about 3 cm and 10 cm. Theminimum distance between the distal end of the pusher attachment and theopening may be between about 3 cm and 9 cm. The minimum distance betweenthe distal end of the pusher attachment and the opening may be betweenabout 3 cm and 8 cm. The minimum distance between the distal end of thepusher attachment and the opening may be between about 2 cm and 10 cm.

The tether connecting the bead and the stent, may be made available invariable diameters. Particularly, in the event that drainage would beuseful. For example, occasionally, after the ureter has been traversedwith an instrument it may be traumatized causing edema and obstructionof the urinary flow. When there is swelling in the intramural (bladderportion) of the ureter, drainage of the ureter may assist with reducingthe swelling. Generally, a stent will allow for drainage of the ureter,but in some instances the swelling may be such that the stent alone isnot sufficient to provide drainage, in particular, where a shortenedstent is used. In such circumstances the tether may also assist withdrainage of the ureter. A larger diameter tether or possibly even a flattether may help with drainage. Alternatively, tether with othernon-circular cross-sections may be appropriate in the circumstances.

BRIEF DESCRIPTION OF THE DRAWINGS

In drawings which illustrate embodiments of the invention:

FIG. 1 is a side view of a modified pusher apparatus according to afirst embodiment;

FIG. 2 is a side view of a modified pusher apparatus according to asecond embodiment, wherein the area adjacent the opening is reinforced;

FIG. 3 is a side view of a pusher attachment apparatus according to anembodiment adjacent to an unmodified pusher;

FIG. 4 is a partial cross-sectional view of the modified pusherapparatus of FIG. 1, adjacent to a stent assembly having a tether and abead, all threaded over a guide wire, wherein the bead is positionedwithin the opening of the modified pusher apparatus;

FIG. 5 is a cross-sectional view of the modified pusher apparatus ofFIG. 1, positioned within a cytoscope, threaded over a guide wire, witha bead positioned within the opening of the modified pusher apparatus;

FIG. 6 illustrates a shortened stent positioned within the ureter and atethered bead suspended in the bladder;

FIG. 7 illustrates a shortened stent positioned within the ureter and aprior art tethered bead suspended in the bladder; and

FIG. 8 illustrates a shortened stent positioned within the ureter and alarger tethered bead than in FIG. 6, suspended in the bladder.

DETAILED DESCRIPTION

As used herein a “bead” is meant to include any ferromagnetic member.Ferromagnetic as used herein is meant to include materials which maycomprised of iron, nickel, chromium, or cobalt or combinations thereofand various alloys, such that the bead is attracted to a magnet. Forexample, a bead may be made from ferromagnetic stainless steel.Furthermore, beads are preferably biocompatible. For example, astainless steel bead may be coated with a smooth layer of polymer, forexample, polytetrafluoroethylene. A “biocompatible” bead or a beadcoated with a biocompatible coating, may prevent the reaction of thebead with urine or bile, or other bodily fluids in which the bead may beplaced. Furthermore, the bead may itself be a magnet. Beads as describedherein are generally biocompatible, rounded, perforated, andferromagnetic. For example, a bead may be made from a rare earth magnetor a stainless steel having magnetic properties.

A pusher is essentially a hollow tube, which may be made in a variety ofdiameters and having a range of wall thicknesses, and may be selected toensure compatibility for use with a given stent. A pusher may be madefrom high durometer (stiff), biocompatible, polymers and polymer blends(for example, polyurethane, high density polyethylene, nylon, etc. andblends thereof), as known in the art.

A holder as used herein, is meant to include any member that is capableof retaining a bead within an opening of a modified pusher apparatus ora pusher attachment, to facilitate the insertion of a guide wire throughthe bead, while the bead is within the opening of the modified pusherapparatus or the pusher attachment. The holder may be removed afterinsertion of a guide wire or may remain associated with the modifiedpusher apparatus or the pusher attachment, but be in a release positionso that when the guide wire is removed during s stent insertion, thebead may be released from the modified pusher apparatus or the pusherattachment. A commercial package containing such a holder, mayfacilitate loading of a selected guide wire, for insertion into theapparatus. A holder may be internal or external or a combinationthereof. Furthermore, a holder may, for example, take the form of aremovable wrapper, a clip, a mandrel, a wedge, an adhesive surfacemodification etc. An adhesive surface modification, may be prepared suchthat the adhesive dissolves when in situ (for example, in urine, at bodytemperature, etc.). Such a system allows for the selection of the bestguide wire to suit the patient or the personal preferences of the user.For example, guide wires may be chosen for their frictional properties(for example, a hydrophilic coating may provide for less friction) ortheir ‘pushability’.

A mandrel, as used herein, may be a wire that resides within themodified pusher apparatus or a pusher attachment, to hold the beadwithin the opening of the modified pusher apparatus or the pusherattachment until the guide wire is inserted. The mandrel may be sized tofit within the bead with the guide wire or such that it is pushed out ofthe bead as the guide wire is inserted.

A wrapper, as used herein, may be any type of protective covering thatis capable of retaining a bead within the opening of a modified pusherapparatus or a pusher attachment, to facilitate the insertion of a guidewire through the bead. Such a wrapper may be removed once the guide wireis inserted through the bead.

Referring to FIG. 1, a modified pusher apparatus according to a firstembodiment is shown generally at 10. The inner hollow portion or lumenof the pusher is shown at 14 and the distal end of the modified pusherapparatus is shown at 19. The modified pusher apparatus has a receptacle17, which is defined by an opening 15. The lumen of the pusher mayreceive a guide wire (not shown in FIG. 1) and the receptacle 17 issized and positioned near the distal end of the pusher 19 to receive atethered bead attached to the proximal end of the stent (the bead andstent are not shown in FIG. 1).

Referring to FIG. 2, a modified pusher apparatus according to a secondembodiment is shown generally at 10. Similar to FIG. 1, the inner hollowportion or lumen of the pusher is shown at 14 and the distal end of themodified pusher apparatus is shown at 19. The modified pusher apparatushas a receptacle 17, which is defined by an opening 15. The lumen of thepusher may receive a guide wire (not shown in FIG. 2) and the receptacle17 is sized and positioned near the distal end of the pusher 19 toreceive a tethered bead attached to the proximal end of the stent (thebead and stent are not shown in FIG. 2). However, the modified pusher ofFIG. 2 has a reinforced area 20 adjacent the opening to maintain thestructural integrity of the pusher tube despite the opening 15 in thewall of the pusher tube. The reinforced area 20 may be made of adifferent material than the remainder of the pusher or the reinforcedarea 20 may have added material that is the same as or different thanthe remainder of the pusher. Furthermore, the reinforced area 20 may bemade of a material that is less flexible than the remainder of thepusher or the reinforced area 20 may have added material that is lessflexible than the remainder of the pusher. The reinforcement applied inthe reinforced area 20 adjacent the opening and the size of the area tobe reinforced 20 may depend on a number of factors, which may includethe size of the opening 15, the shape of the opening 15, the propertiesof the material from which the remainder of the pusher is made, theproperties of the material adjacent the opening 15, the properties ofthe material defining the borders of the receptacle 17, and the use inwhich the pusher is to be implemented. In view of the above a person ofskill in the art would be well aware of the reinforcement that may beapplied to maintain the structural integrity of the pusher. Thereinforced area, for example, may be made from stainless steel oranother alloy.

Referring to FIG. 3, a pusher attachment apparatus according to anembodiment is generally shown at 100. The inner hollow portion or lumenof the pusher attachment apparatus is shown at 140, the inner hollowportion or lumen of the pusher is shown at 141, and the distal end ofthe pusher apparatus is shown at 190. The pusher attachment apparatushas a receptacle 17, which is defined by an opening 15. The lumen of thepusher may receive a guide wire (not shown in FIG. 3) and the receptacle17 is sized and positioned to receive a tethered bead attached to theproximal end of the stent (the bead and stent are not shown in FIG. 3).The pusher attachment apparatus may be designed, to be attached to anystandard pusher apparatus to allow for the positioning of a bead, whichis tethered to a stent, within the receptacle 17.

Referring to FIG. 4, a modified pusher apparatus according to a firstembodiment is shown in a partial cross-section generally at 10, adjacenta partial cross-section of a shortened stent 30. The stent 30 ispositioned along a guide wire 50 at the distal end 19 of the modifiedpusher 10, whereby the distal end 19 of the modified pusher 10 isadjacent to the proximal end 39 of the stent 30. The guide wire 50 isshown, from proximal to distal (left to right), passing through theinner hollow portion or lumen 14 of the modified pusher apparatus 10,passing through the bore or perforation in the bead 40, through theremainder of the lumen 14 of the modified pusher apparatus 10, andpassing through the inner hollow portion or lumen 34 of the stent 30.The modified pusher apparatus has a receptacle 17, which is defined byan opening 15. The bead 40 is shown positioned near the distal end ofthe pusher 19, within the receptacle 17 and with the guide wire passingthrough the bore within the bead. A tether 60 is shown looping aroundthe exterior of the stent and passing through a stent perforation 36,passing through the inner hollow portion or lumen 34 of the stent 30 tothe proximal end of the stent 39, then along the outer surface of themodified pusher apparatus 10, to the bead 40 and through the tetheropening 43 of the bead, wherein the tether opening as shown is generallyextend through the bead perpendicular to the long axis of the bead. Asshown in FIG. 4, only one side of the tether loop is shown between thebead and the stent lumen.

Referring to FIG. 5, a modified pusher apparatus according to a firstembodiment is shown in a partial cross-section generally at 10,positioned within the lumen 74 of a cytoscope 70. The bead 40 is shownin cross-section positioned within the receptacle 17 adjacent the distalend 19 of the modified pusher 10, whereby the distal end 19 of themodified pusher 10 is adjacent to the distal end 79 of the cytoscope 70.Also shown, is the bead tether opening 43, but the tether is not shown.The guide wire 50 is shown, from proximal to distal (bottom left to topright), passing through the inner hollow portion or lumen 14 of themodified pusher apparatus and through the lumen of the cytoscope 74,passing through the bore or perforation in the bead 40, through theremainder of the lumen 14 of the modified pusher apparatus 10, andpassing through the inner hollow portion or lumen 34 of the stent 30.

Referring to FIGS. 6, 7, and 8, shortened stents are shown positionedwithin the ureter 90, following insertion with the insertion apparatusremoved (i.e. cytoscope, pusher and guidewire). The stent assembly,which includes the shortened perforated stent 30, tether 60, and bead 40are shown in FIGS. 6, 7, and 8 with three different bead designs. Thebead design in FIG. 7 is reproduced from the PCT applicationPCT/CA99/00405. The positioning of the stent assembly is such that theproximal end of the stent 39 is positioned within the ureter 90 and awayfrom the ureteral orifice 85 and whereby the bead 40 is suspended in thebladder 80 by the tether 60, which passes through the bead tetheropening 43. FIG. 7 also shows a passage for a positioning line 45 withinthe bead (positioning line not shown). FIG. 6 shows a larger bead designrelative to FIG. 8. Nevertheless, the shorter bead designs of FIGS. 6and 8 may permit better rotation on the tether, as compared to the beadof FIG. 7, which may assist in release of the tethered bead from thepusher apparatus or pusher attachment (not shown in FIGS. 6-8).

Referring to FIGS. 4-8, the bead tether opening 43 as shown is generallyat a midpoint in the bead 40 to allow the bead to lie perpendicular tothe ureteric orifice 85 and prevent migration up the ureter 90.

The operation of the modified pusher apparatus for the insertion of ashortened stent 30 into a ureter 90 may be described as follows:

-   -   a cytoscope 70 is inserted into the bladder, and a guide wire 50        is passed up the cytoscope lumen 74 to the bladder and up the        ureter into a kidney;    -   a shortened stent 30 is threaded onto the guide wire 50, without        threading the bead 40, followed by the modified pusher apparatus        10 until the guide wire approaches the receptacle 17,    -   the bead 40 tethered to the stent 39 is positioned within the        receptacle 17 such that the guide wire 50 may pass through the        bead and towards the proximal end of the pusher (alternatively,        the stent 30, pusher 10, bead 40 and guidewire 50 may be        preassembled to allow for insertion as a unit);    -   the shortened stent 30 followed by the modified pusher apparatus        10, with the bead 40 positioned within the receptacle 17 and        held in place by the guide wire, are advanced up the guide wire        50 and through the cytoscope 70 into the bladder 80;    -   the shortened stent 30 and the modified pusher apparatus 10 are        further advanced up the ureter so that the hook or pigtail (not        shown) on the distal end of the stent is positioned within the        kidney and the proximal end of the stent 39 is positioned within        the ureter 90 as shown in FIGS. 6-8;    -   the cytoscope 70, which is situated in the bladder 80, is used        to visually confirm (fluoroscopic confirmation) the correct        positioning of the stent 30 based on the position of the        modified pusher apparatus 10 relative to the uretal orifice 85        (such a fluoroscopic confirmation may be simplified, where the        pusher has markings or gradations so that the operator can gauge        the depth of the stent within the ureter);    -   the modified pusher apparatus 10 is held in position adjacent        the proximal end of the stent 39, while the guide wire 50 is        removed so that the shortened stent 30 does not slide down the        ureter 90 (from distal to proximal) as the guide wire is        withdrawn from the ureter; and    -   the modified pusher apparatus 10 is withdrawn into the        cystoscope and removed together with the cytoscope 70 (to avoid        damaging the urethra with the receptacle 17).

Removal of the stent 30 may be accomplished by a non-surgical procedurethat does not even require endoscopy. As described in an earlier patentapplication (WO99/58083) a retrieval catheter (not shown), whichcomprises a conventional catheter that is modified to mount a magnet atthe distal tip of the catheter. The magnet may also be covered with abiocompatible coating and/or may be rounded to prevent injury to thepatient. The magnet-tipped end of the retrieval catheter is inserted,through the urethra and into the bladder, where the catheter tipmagnetically engages the suspended bead 40. As the catheter is withdrawnthe bead 40 and tether-connected stent 30 are pulled from the ureter andexplanted from the patient.

As the retrieval catheter approaches the bead 40, the magnetic fluxacting on the bead 40 should be sufficient to cause the bead to rotaterelative to the tether from its normal, suspended position, so that oneof the ends of the bead 40 rotates on the tether to contact the tip ofthe retrieval catheter. Accordingly, the bead will be oriented generallycoaxially with the end of the retrieval catheter. If this orientation isnot attained in the bladder, as the retrieval catheter and bead enterthe urethra passage, the urethra will likely cause the axial alignmentof the bead 40 with the retrieval catheter, which is desired forcomfortable removal of the bead through the urethra. It will beappreciated that this rotation of the bead will be assured where thebead is magnetized, and one of its ends has a polarity opposite that ofthe magnet on the retrieval catheter.

Alternatively, the bead 40 could be a magnet and the retrieval cathetertipped with ferromagnetic material or another magnet. Although arare-earth magnet is preferred, other types, including electromagnetscould be employed with the retrieval catheter. In addition, the bead maybe of a more ball shape FIGS. 6 and 8, rather than the elongated bead ofFIG. 7.

Although various embodiments of the invention are disclosed herein, manyadaptations and modifications may be made within the scope of theinvention in accordance with the common general knowledge of thoseskilled in this art. Such modifications include the substitution ofknown equivalents for any aspect of the invention in order to achievethe same result in substantially the same way. Numeric ranges areinclusive of the numbers defining the range. The word “comprising” isused herein as an open-ended term, substantially equivalent to thephrase “including, but not limited to”, and the word “comprises” has acorresponding meaning. As used herein, the singular forms “a”, “an” and“the” include plural referents unless the context clearly dictatesotherwise. Thus, for example, reference to “a thing” includes more thanone such thing. Citation of references herein is not an admission thatsuch references are prior art to an embodiment of the present invention.Any priority document(s) and all publications, including but not limitedto patents and patent applications, cited in this specification areincorporated herein by reference as if each individual publication werespecifically and individually indicated to be incorporated by referenceherein and as though fully set forth herein. The invention includes allembodiments and variations substantially as hereinbefore described andwith reference to the examples and drawings.

What is claimed is:
 1. A commercial package comprising: (a) a guidewire; (b) a stent assembly for keeping a body channel open and having ashortened stent and a tethered bead for retrieval of the shortenedstent, where the shortened stent and bead are pushed over the guidewire; and (c) a pusher apparatus, for the insertion of the shortenedstent comprising: a hollow tube having a distal end and a proximal end,wherein the hollow tube has a diameter similar to or the same as thediameter of the shortened stent, such that the distal end of the pusheris adapted to be positioned adjacent the proximal end of the shortenedstent; and an opening defined in a peripheral wall of the pusherapparatus near the distal end, where the opening reaches a hollowportion of the pusher apparatus to form a receptacle and the receptacleis sized to allow for the positioning therein of a ferromagnetic beadtethered to the shortened stent, where the ferromagnetic bead has a boretherethrough, such that when the bead is positioned within thereceptacle, the bore is coaxial with the hollow tube, such that, whenthe guide wire extends longitudinally through the pusher apparatus, theguide wire passes through the bore of the tethered ferromagnetic beadand wherein removal of the guide wire from the bore facilitates releaseof the ferromagnetic bead from the receptacle.
 2. A commercial packagecomprising: (a) a stent assembly for keeping a body channel open andhaving a shortened stent and a tethered bead for retrieval of theshortened stent, the shortened stent and bead being adapted to be pushedover a guide wire; and (b) a pusher apparatus, for the insertion of theshortened stent, wherein, the pusher apparatus comprises: a hollow tubehaving a distal end and a proximal end, wherein the hollow tube has adiameter similar to or the same as the diameter of the shortened stent,such that the distal end of the pusher is adapted to be positionedadjacent the proximal end of the shortened stent; and an opening definedin a peripheral wall of the pusher apparatus near the distal end, wherethe opening reaches a hollow portion of the pusher apparatus to form areceptacle and the receptacle is sized to allow for the positioningtherein of a ferromagnetic bead tethered to the shortened stent, wherethe ferromagnetic bead has a bore therethrough, such that when the beadis positioned within the receptacle, the bore is coaxial with the hollowtube and wherein the ferromagnetic tethered bead is retained within theopening by a holder until a guide wire is inserted, such that, when theguide wire extends longitudinally through the pusher apparatus, theguide wire passes through the bore of the tethered ferromagnetic beadand wherein removal of the guide wire from the bore facilitates releaseof the ferromagnetic bead from the receptacle.
 3. The commercial packageof claim 2, wherein the holder is external.
 4. The commercial package ofclaim 2, wherein the holder is internal.
 5. The commercial package ofclaim 2, wherein the holder is at least one of a wrapper and a mandrel.